In a large-scale integration of electric vehicles (EVs) to the transportation sector, it becomes ... more In a large-scale integration of electric vehicles (EVs) to the transportation sector, it becomes more challenging to provide an acceptable level of service to EV users who already suffer from EV’s short range and long charging time. Because of the latter, charging facilities can be easily overloaded, leading to intolerable service delays. Achieving an acceptable level of service will require an extensive upgrade for power networks. However, it is necessary to make sure that existing charging resources are efficiently utilized before taking such expensive decision. In this paper, we provide a user-oriented EV control scheme based on the efficient assignment of EVs to charging stations. The key performance indicator is the average time spent by the user from requesting the charging service to accessing it. Our direction is thus opposing to that of the majority of EV-related studies which sacrifice user convenience for achieving utility benefits. The methodology we use depends on defining a queueing model to facilitate the management of a dynamic population of EVs, then developing an EV assignment algorithm based on the Lyapunov optimization method. Our scheme is compared to that of other two dynamic assignment schemes which are the nearest-station policy and join-the-shortest queue policy.
Future energy grids are expected to rely extensively on controlling consumers’ demands to achieve... more Future energy grids are expected to rely extensively on controlling consumers’ demands to achieve an efficient system operation. The demand-side of the power network is usually constituted of a large number of low power loads, unlike energy production which is concentrated in a few numbers of high power generators. This research is concerned with supporting the management of numerous loads, which can be challenging from a computational point-of-view. A common approach to facilitate the management of a large number of resources is through resource aggregation (clustering). Therefore, the main objective of our research is to develop efficient load aggregation methodologies for two categories of demands: residential appliances and electric vehicles. The proposed methodologies are based on queueing theory, where each queue represents a certain category (class) of demand. Residential appliances are considered in the context of two demand management problems, where the first aims to minim...
2009 Joint IEEE North-East Workshop on Circuits and Systems and TAISA Conference, 2009
A programmable spread spectrum clock generator (PSSCG) using fractional-N phase-locked loop (PLL)... more A programmable spread spectrum clock generator (PSSCG) using fractional-N phase-locked loop (PLL) is presented. Spreading is achieved by modulating the feedback divider using a triangular wave through a ΣΔ modulator. In order to allow wide spreading ratios a new technique is adopted to keep the triangular wave within the input range of the ΣΔ modulator. The clock frequency is programmable from 8–280 MHz with center and down spreading (0.5%, 1%, 2%, 4%). The RMS period jitter is 8.7 ps at 280 MHz. The electromagnetic interference (EMI) reduction is 18.1 dB at 4% center spreading. The proposed PSSCG is designed using a CMOS 0.18μm 6-metal technology and has an active area of 0.66 × 0.45 mm2.
2012 29th National Radio Science Conference (NRSC), 2012
Abstract Cellular dwell time plays an important role in calculating teletraffic performance metri... more Abstract Cellular dwell time plays an important role in calculating teletraffic performance metrics such as call blocking and forced termination probabilities. However to our knowledge, cellular teletraffic performance had not been calculated under the assumption ...
In a large-scale integration of electric vehicles (EVs) to the transportation sector, it becomes ... more In a large-scale integration of electric vehicles (EVs) to the transportation sector, it becomes more challenging to provide an acceptable level of service to EV users who already suffer from EV’s short range and long charging time. Because of the latter, charging facilities can be easily overloaded, leading to intolerable service delays. Achieving an acceptable level of service will require an extensive upgrade for power networks. However, it is necessary to make sure that existing charging resources are efficiently utilized before taking such expensive decision. In this paper, we provide a user-oriented EV control scheme based on the efficient assignment of EVs to charging stations. The key performance indicator is the average time spent by the user from requesting the charging service to accessing it. Our direction is thus opposing to that of the majority of EV-related studies which sacrifice user convenience for achieving utility benefits. The methodology we use depends on defining a queueing model to facilitate the management of a dynamic population of EVs, then developing an EV assignment algorithm based on the Lyapunov optimization method. Our scheme is compared to that of other two dynamic assignment schemes which are the nearest-station policy and join-the-shortest queue policy.
Future energy grids are expected to rely extensively on controlling consumers’ demands to achieve... more Future energy grids are expected to rely extensively on controlling consumers’ demands to achieve an efficient system operation. The demand-side of the power network is usually constituted of a large number of low power loads, unlike energy production which is concentrated in a few numbers of high power generators. This research is concerned with supporting the management of numerous loads, which can be challenging from a computational point-of-view. A common approach to facilitate the management of a large number of resources is through resource aggregation (clustering). Therefore, the main objective of our research is to develop efficient load aggregation methodologies for two categories of demands: residential appliances and electric vehicles. The proposed methodologies are based on queueing theory, where each queue represents a certain category (class) of demand. Residential appliances are considered in the context of two demand management problems, where the first aims to minim...
2009 Joint IEEE North-East Workshop on Circuits and Systems and TAISA Conference, 2009
A programmable spread spectrum clock generator (PSSCG) using fractional-N phase-locked loop (PLL)... more A programmable spread spectrum clock generator (PSSCG) using fractional-N phase-locked loop (PLL) is presented. Spreading is achieved by modulating the feedback divider using a triangular wave through a ΣΔ modulator. In order to allow wide spreading ratios a new technique is adopted to keep the triangular wave within the input range of the ΣΔ modulator. The clock frequency is programmable from 8–280 MHz with center and down spreading (0.5%, 1%, 2%, 4%). The RMS period jitter is 8.7 ps at 280 MHz. The electromagnetic interference (EMI) reduction is 18.1 dB at 4% center spreading. The proposed PSSCG is designed using a CMOS 0.18μm 6-metal technology and has an active area of 0.66 × 0.45 mm2.
2012 29th National Radio Science Conference (NRSC), 2012
Abstract Cellular dwell time plays an important role in calculating teletraffic performance metri... more Abstract Cellular dwell time plays an important role in calculating teletraffic performance metrics such as call blocking and forced termination probabilities. However to our knowledge, cellular teletraffic performance had not been calculated under the assumption ...
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